High cleanliness of portable clean-unit-box to unite clean-unit system platforms (CUSPs) and CUSP units

As a platform for nano-science and technology, cleanliness in a compact and local clean environment, i.e. a portable clean-unit-box (CUP), is reported for establishing a large-scale network of an ultrahigh clean environment platform towards cross-disciplinary research. Analyses of experimental results indicate that the CUP has cleanliness of ISO class ~2, which is one order of magnitude better than the conventional wafer transportation cleanbox.